1. Field of the Invention
The present invention generally relates to a rapid start-up, auxiliary power, and air preheating device of high temperature fuel cell systems, and more particularly to a device having a heat exchanger for preheating air or a front-end system of an integrated reformer in a high temperature fuel cell system for heat a gas entering the reformer, while generating an auxiliary power to drive the electric device in the system, and the device can process the remaining gases introduced into a fuel cell stack for a post-combustion, and it is a rapid start-up, auxiliary power and air preheating device, wherein the direct combustion solid oxide fuel cell in the device can generate electric power instantaneously by a flame combustion of a hydrogen-rich fuel. The device of the invention can be installed in another waste gas post-combustion system to serve as an additional auxiliary power source.
2. Description of the Related Art
In recent years, governments and private sectors of different countries invest tremendous manpower and capitals for the research and development of fuel cell technologies. Since fuel cells are energy converting devices with high efficiency and low pollution, and whose anode supplies a fuel and whose cathode supplies an oxidizing agent, therefore chemical energy can be converted into electric energy by an electrochemical reaction directly. The solid oxide fuel cell conducts oxygen ions through a solid electrolyte for an electrochemical reaction to generate electric energy and operates together with a thermal turbine system to provide the advantages of a high energy conversion efficiency, a low discharge of polluted gases, and diversified applications of the fuel.
The preliminary objective of the research and development of solid oxide fuel cell systems is to supply electric energy for an electric generator in a power plant at a fixed location. In the development process of the solid oxide fuel cell systems, there are various different designs of cell stacks, and three of the common designs of the electrolyte of high-temperature fuel cells are tubular, planar and molten designs. Oxygen ions are transmitted quickly in the electrolyte at a high temperature, and the output power density is large, and thus there is no flooding phenomenon of the low-temperature cell. However, it is necessary to overcome two issues to achieve the practical applications of the planar solid oxide fuel cell. Firstly, it takes a long start-up lag for the high temperature fuel cell systems to reach a specific working temperature range. Secondly, a cell stack has two major problems, respectively metal fatigue and thermal cracking when the high-temperature fuel cell is operated at a high temperature.
In the present high temperature fuel cell systems, the ambient temperature of the whole system is approximately equal to 40˜950° C., and thus insulating cotton and insulating ceramic can be used for isolating two areas, wherein one area refers to the high-temperature module having high ambient temperature and including one high-temperature fuel cell module, one gas divided pipe, and one heat exchanger or one integrated reformer for preheating air, and an energy recycle unit, and another area refers to the support module which is a part of the system control and gas and combustion input, having one high-performance fan, one control panel (fuel input end and power output end), one control system unit and one power inverter.
In general, a high temperature fuel cell system usually use a heat exchanger or an integrated reformer for preheating air, and a thermal couple component for driving, and whose electric power source is coupled to a fuel cell or an additional power supply system for heating fuels and gases entering into the cell. R.O.C. Pat. No. M323119 has disclosed such technology, but an additional power source is required, no matter how high is the thermal conversion efficiency. If it is necessary to increase the system temperature quickly, the power consumption is also increased, and thus the prior art not only consumes much time, but also lowers the overall performance of the fuel cell generation system.
To overcome the issue of operating a high temperature fuel cell at a high temperature for a long time that causes a thermal stress and a possible crack of the cell stack, R.O.C. Pat. Nos. M281305 and M273828 disclose an improved design of using a channel structure of a connecting plate and a stopping block to overcome the cracking issue of a cell stack. In addition, a composite electroplating method or a newly developed cell materials, cells or protecting films as disclosed in R.O.C. Pat. Nos. I2343216, I2343216, I253779, 200603474, and 00591814 are disclosed. However, these patented technologies still cannot prevent the non-uniform temperature distribution effectively and has no significant effect on the quick startup of the fuel cell at all.
The apparatus in accordance with the present invention can be installed at a front-end device of a heat exchanger or an integrated reformer for preheating a gas and having a rapid start-up, auxiliary power and air preheating device, while generating an auxiliary power during the process of heating and combusting the gas and reducing the start-up lag of the high temperature fuel cell system to reach a specific working temperature range, such that the cell stack can achieve the rapid start-up and the working temperature effectively, and provide an additional electric power to improve the system performance. The present invention is novel and there is a need for improving the high temperature fuel cell systems, and thus the inventor of the present invention based on years of experience in the related industry to conduct extensive researches and experiments, and finally simulated and developed a fuel cell system in accordance with the present invention.